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    <title>Document</title>
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    <script>
let str = "adsfsgEREvg啦啦啦啦啦dfsfr";
str = str.replace(/[a-zA-Z]/g,content=>{
	console.log(content)
	// content=>每一次正则匹配的结果
	return content.toUpperCase()===content?content.toLowerCase():content.toUpperCase()
})
console.log(str)//=>ADSFSGereVG啦啦啦啦啦DFSFR


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